Hi all. I'm new to this forum. I have a question about my trooper. It has 156,000 miles on it and I'm planning on changing the timing belt, water pump and tensioner. The replacement of the parts should be straight forward, but should i be worried about the timing and such. I bought it new and has never had it changed so it's way past due. I've seen some sites where other have pictures that show their removeal and replacement procedure. Are there any procedures for a timing belt replacement for my model on this site or any other? Any and all replies will be greately appreciated. Thanks in advance.

Hi and welcome to the planet!
EDIT:I believe we are talking about the Isuzu 3.5 engine. You should really get a service manual, but if you search on this forum you should be able to find some very good posts giving you all the info you need to do this job.
My best advice is........BEFORE removing the timing belt, make sure that all the alignment marks are in the correct postion by, if necessary, rotating the engine enough in order to line them up. It may take a few revolutions of the crankshaft to do that, but it is the best and safest way to do it. You will need to (obviously) remove the timing covers first, but then it shoud be able to be done with the directions you can find on this site or in a service manual.
Your engine had the newer timing gears in the heads so getting the timing marks lined up right in the first place is the way to go. Getting the gears synched up by not doing so is not an easy thing to do, especially for the inexperienced. I am saying that based on what I have read about it.
The suggestion to put you year, model and engine trans combo in your signature is a good one, you will get better responses and searches are easier too!
Good luck, let us know how you do or if you need more info.

Last edited by atfdmike on Mon Jan 28, 2008 7:52 am, edited 1 time in total.

atfdmike wrote:...I believe we are talking about the Isuzu 3.5 engine, so yes, you need to be careful when doing a timing belt change. It is imperative that timing be right since this is an interference engine .....

this is NOT an interference engine. here's the text of DA WORD ON INTERFERENCE/NONINTERFERENCE ISUZU ENGINES FROM DA EXPERT JLEMOND

JLEMOND wrote:ALL ISUZU V6 ENGS ARE NON INTERFERENCE ENGS FROM 92TROOPER ALL THE WAY TO 2002 AND THE RODEOS 93 THRU THE 2003 MODEL YEAR,

OK, dang it, I did blow it and I apologise! I hope it did not make things more confusing for others. No excuse, I keep getting the DI motor and standard 3.5 mixed up for some reason. My motives were good, I just had a brain freeze.
I think I just got a new resolution to only offer advice on the engines and model I have rather than try and remember all the different permutations! Should have done this sooner!

Thanks for all of the info. I will try to find a good service manual to start with. I'm wondering how hard will it be to line up my timing marks by hand? I will look over the other threads that some of you have provided to get a better picture of what i have in store for me. Thanks again.

jbjunior66 wrote:Thanks for all of the info. I will try to find a good service manual to start with. I'm wondering how hard will it be to line up my timing marks by hand? I will look over the other threads that some of you have provided to get a better picture of what i have in store for me. Thanks again.

it's all spelled out how to do it. just take your time.

you can get the factory manuals from www.helminc.comthere are downloadable ones available search this site.

I ordered a service manual from helminc.com a few days ago. They called me back to tell me that the manual is on back order for at least 6 weeks. Does anyone have any idea on how to align your timing marks after all the covers are off? Do i have to bump the engine over or something like that or what. Any ideas will help. Thanks

jbjunior66 wrote:I ordered a service manual from helminc.com a few days ago. They called me back to tell me that the manual is on back order for at least 6 weeks. Does anyone have any idea on how to align your timing marks after all the covers are off? Do i have to bump the engine over or something like that or what. Any ideas will help. Thanks

before the manual comes, read all the other links that have been provided here, plus others you can find with Search. it will calm your jitters about doing this.

you can bump the starter if you want, but more controlled is to temp put the pulley and bolt back on and just turn it, clockwise, by hand with your socket and breaker bar.

it's an especially good idea with the dohc, as i understand it, to keep the cams in the same positions, but if you do move them or you want to make sure everytning is at it should be, there is the procedure to align all correctly from scratch. read those links, and the manual when it comes.

Just finished the same job in my 94 Rodeo 3.2. The Haynes manual, while thin on some important content generally, had a good diagram and fairly decent explanation of lining up the timing marks. It's easier to understand once you have the timing belt covers off.

Do yourself a favor and get some white out or a silver metallic marker pen and a ruler. There is a recessed line in the metal and a painted white mark on the OUTSIDE edge of each camshaft sprocket, and a dot on the INSIDE (back) of the timing cover (against the valve covers). Problem is, this means they're about 2" apart (front to back) and you'll be looking at it from slightly above since the radiator is in the way of your line of sight to look at it level. Eyeballing this is almost impossible to do accurately. So, touch the silver marker to the dot on the covers to highlight it, and draw a perfectly level line on the old belt (the old line is long gone by now.) This will make it easier to line up.

You need to make sure ALL THREE gears are in proper alignment -the crankshaft and the two camshafts. As a ballpark, this means (on my 3.2 anyway) that the passenger's side camshaft mark will be in about the 10 o'clock position, the driver's side in the 2 o'clock, and the crankshaft in about the 9 o'clock. The mark on the crankshaft sprocket is hard to see, but it should be 180 degrees away from the "keyway" tab on the crank, meaning the crank keyway tab will be at about the 3 o'clock.

God forbid anyone should try to time it using those clock positions only, but they're useful as a general guide.

Once you have the shroud, fan, fan mount, and timing covers off, it will make more sense. To line up the marks, take the drivebelts off and remove the crankshaft drivebelt pulley (you may need a large gear puller), then reinstall the bolt that held the pulley on. Use a 24 mm socket to turn the crank a couple of full revolutions of the belt until everything lines up. When you'd be willing to bet your engine that it's all lined up, you can remove the timing belt and start with the new installation - but remember, this is "one-tooth" tolerance. You can't be even a little off. This is easier said than done, as it's easy to get slack in the wrong place and pull one of the camshafts out of alignment while trying to get the new belt on. If your timing is good now, the goal is to take the timing belt off and DO NOT MOVE the crank or either camshaft until the new one is on and the slack is pretty equal all the way around (in other words, make sure that you have absolutely minimal slack between the two camshaft sprockets where the belt dips down to the water pump pulley - if this is loose, you'll play hell trying to get enough slack to make everything else fit.)

You may have to experiment with different orders of slipping the belt onto the various sprockets and pulleys - I could NOT get mine to go on in the order that the Haynes manual said (crankshaft first, then passenger's side camshaft, then driver's side camshaft anf finish by pulling down onto the water pump pulley) and when I tried, it threatened to pull the camshaft pulleys out of alignment inward toward each other - a big no-no.

My passenger's side camshaft had a little bit of spring action in it - when I had it all installed, the pressure on the water pump pulley would pull it about a tooth clockwise inward toward the water pump pulley - but then when I pulled the pin on the hydraulic tensioner to take up the tiny slack between the passenger side camshaft pulley and the crankshaft, it pulled it back into perfect position.

Also remember that the important thing isn't to get the BELT marks to line up exactly (they should, but that doesn't mean a lot... the belt itself can be anywhere along the rotation cycle so long as the camshafts and crankshaft line up with their marks and stay there), but rather to make sure the marks on the CAMSHAFT sprockets line up with the dots on the back timing belt cover, and then keep them that way. The marks on the belt simply serve as a good guide to make sure the other two are lined up with each other and you generally have taken up the slack in the right places. Don't let any of your 3 sprockets move, but the passenger's side pulley may turn just a fraction of an inch during the final belt installation to the exact same degree that it will rotate back when the hydraulic tensioner is installed. Pick a tooth or two on each sprocket and use a marker if you have to in order to get a good reference point between the sprockets and a fixed point on the engine, and use binder clips from an office supply if you need to get the timing belt to keep its teeth down on the camshafts while adjusting.

Thanks Wolfgang. Did you have to pull any of your sparkplugs to get the engine to rotate? BTW I could not find a haynes for my model trooper. What gives. I have a pretty good idea as how to procede from here. I shouldn't have any problems after I get the timing marks lined up. Thanks for all the help. The dealer quoted me $700 for the job. That included the water pump also. I can save over half of that if I do it myself. Which I will do.

I've replaced 2 timing belts on my V6 and found that, in addition to removing the timing-belt tensioner pulley, if you also remove the idler pulley (even if you are not replacing it) it makes fitting and lining up the belt marks so much easier. Then install the idler, then the tensioner.

jbjunior66 wrote:Thanks Wolfgang. Did you have to pull any of your sparkplugs to get the engine to rotate?

you don't need to pull the plugs, but of course it's easier.

BTW I could not find a haynes for my model trooper. What gives. I have a pretty good idea as how to procede from here. I shouldn't have any problems after I get the timing marks lined up.

famous last words, perhaps. if you haven't i urge you to read all the posts on this in the Hall of Fame section, and others that aren't posted there that you discover using Search. here's one in the HofF that applies specifically to the dohc, which has different and important considerations compared to the sohc
http://forum.planetisuzoo.com/viewtopic.php?t=16972

if you have any doubts i urge you to Search for posts by JLEMOND on this subject.

and if you have any other doubts i urge you to consider coming up with the bucks for the isuzu factory service manual available here
www.helminc.com

The other positive thing about pulling the plugs is that when you have reassembled and are turning it over by the crankshaft with a 24mm socket, the easier turning will reassure you that you don't have any valve resistance due to misalignment that wasn't there before. (You'd most likely know anyway.)

I didn't pull my plugs. Would have made the turning over easier, but saved a step - had they been due for cleaning/replacement, though, that's as good a time as any.